Small Hydraulic Excavator Arm And Rotating Platform Complex Movement Coordination

The compound movement of arm and swing platform is indispensable during a working loop of hydraulic excavator. The time-using and energy-consumption of this compound movement course account for a considerable proportion. In order to reduce the energy consumption and improve the work efficiency of hydraulic excavator, arm's movement and swing platform's movement must be coordinate with each other in terms of time.Hydraulic system is the key part on hydraulic excavator. As the key component in the excavator hydraulic system, the multitandem valve controls the flow direction of oil and adjusts the flow rate of oil passing through the valve, and that control the excuting component's movement direction and velocity. So, the multitandem valve imposes direct affect on coordination of excavator's compound movement. 3-position-6-port throttle valve is used at large on mini excavator. The inner structure of this type of valve is very complicated. In order to meet the work requirement of mini hydraulic excavator, some notches with different shape and dimention was sloted on the piston endstops of 3-position-6-port throttle valve's spool. There are six piston endstops on the spool of this kind of control valve. Six orifices are formed when the valve body and spool combined. In working condition, three of the six orifices act when the spool moves towards one side, the spare three orifices act when the spool moves towards the other side. In order to coordinate the compound movement of arm and swing platform, the notchs on each piston endstops must be designed reasonably.This paper is about research on the coherence of compound movement between arm and swing platform on SWE15s mini excavator. The purpose is establishing a feasible way to design and analyze the spool of throttle valve. Firstly, this paper points out that notchs on the spool greatly influence the compound movement's coordination between arm and swing platform. Then, Based on the detail analysis to working condition of compound movement and excavator hydraulic system, the simulation models of arm hydraulic loop and swing platform hydraulic loop were built with AMESim. After that, running the simulation models, the simulation results indicated that the existing design of spool notchs could not made the compound movement between arm and swing platform on SWE15s mini excavator meet the requirement. An improved scheme was obtained by further simulation analysis. Finally, corresponding tests were done with existing arm spool and swing spool installed to the target excavator. The test results were accordant with simulation results. That proved the simulation models which were built in this paper is correct. Notch structure was modified according to the improved scheme and a new swing spool was made. The movement of swing platform was tested once again with the new spool installed. The test results prove that the rotating velocity is improved and already meet the design requirement. Furthermore, the simulation method which was explored in this paper proves feasible in guiding the design of spool notches.